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The Skeleton. Bone Facts. Living tissue (hard form of connective tissue) Chief supporting tissue of body 206 bones Babies are born with 270 soft bones 64 of those bones eventually fuse together to make the 206 hard permanent bones that an adult has. - PowerPoint PPT Presentation
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The Skeleton
Bone Facts Living tissue (hard
form of connective tissue)
Chief supporting tissue of body
206 bones Babies are born with
270 soft bones 64 of those bones
eventually fuse together to make the 206 hard permanent bones that an adult has
Male bones tend to be larger and heavier than females
Females pelvic cavity is wider to accommodate childbirth
Functions of the Skeleton Aid in movement of the body
moveable levers which muscles pull to move different parts of the body
To support and protect internal body organs
To produce red and white blood cells 2.6 million red blood cells produced each
second Replace those worn out and destroyed by the
liver To provide a storehouse for minerals
Calcium and phosphorous Protective and supportive framework for
attached muscles and soft tissues that underlie it
Bones Consist of microscopic cells called
osteocytes Organic Part
Protein called bone collagen – fibrous material
Between fibers is jellylike material Inorganic Part
Mineral salts Give bones its hardness and durability
When pressure is applied to a bone: Flexible organic material prevents bone
damage Mineral elements resist crushing under
pressure
Bone Structure Periosteum: outside of the bone
Tough fibrous tissue that contains blood vessels, lymph vessels, and nerves
Necessary for bone growth, repair, and nutrition
Diaphysis Compact bone
Epiphysis End of the diaphysis Contain red marrow where some red blood
cells and some white blood cells are made
Articular cartilage Covers epiphysis Acts as a shock absorber between
two bones at a joint. Endosteum
Lining of the marrow canal to keep the cavity intact
Medullary canal (cavity) Filled with yellow bone marrow
Yellow bone marrow Mostly fat cells, blood vessels, and white
blood cells Functions as a fat storage center
Spongy bone where less strength is needed in the bone Found near the epiphyseal line (growth
plate)
Bone Formation Embryonic skeleton
consists of collagenous protein fibers
During development the body is made up of mostly hyaline cartilage
During the 8th week, ossification beings and bone starts to replace cartilage
As they ossify they become hard and more capable of bearing weight
Bone Growth
Bones grow in length and ossify from the center of the diaphysis towards the epiphyses
Osteoblasts deposit new bone to the outer surface which increases the circumference
Osteoclasts secrete enzymes that digest bony material creating the medullary canal
The length of the bone shaft continues to grow until the growth plates are closed
Bone growth ends for females around 18
Bone growth ends for males around 20-21
New bone growth can occur in a fractured bone at any time
Parts of the Skeleton Axial Skeleton
80 bones Skull, spine, ribs, and sternum
Appendicular Skeleton Made up of the
shoulder girdle, pelvic girdle, and limbs
126 bones 64 bones in the
shoulders and upper limbs
62 bones in the pelvis and lower limbs
Types of Bone Flat
Thin, flattened, and usually a bit curved
Serve protective function Scapula, sternum, ribs, most bones of skull
Irregular Have weird shapes that do not fit other 3
classes Vertebrae, hip, 2 skull bones (sphenoid,
ethmoid bones)
Short Cube-like in shape Found in carpals (wrist) and tarsals
(ankle) Long
Much longer than they are wide All bones of limbs (except patella, carpals,
tarsals) Consists of shaft plus 2 expanded ends
The Skeleton
Skull
Skull
Shoulder
Chest
Sternum
Ribs
Arm
Hand
Upper Extremity
ClavicleScapulaSternumRibsHumerusRadiusUlnaCarpalsMetacarpalsPhalanges
Spine/Pelvis
PelvisSacrumPubic Bone/ Pubis
Sacrum
Pubis
Os Coxa
Leg
Foot
Tarsals
Lower Extremity
The Skeleton